1. Field of the Invention
This invention relates to an apparatus for applying gum or adhesive to an envelope blank during manufacture of an envelope.
2. Description of Related Art
In an application entitled "Apparatus For Manufacturing Envelopes", assigned to the same assignee as the assignee of the present application, Ser. No. 136,493 filed Apr. 3, 1980 now U.S. Pat. No. 4,338,085, an apparatus is disclosed for feeding, scoring, gumming and folding a blank into an envelope. At the gumming station, gum or adhesive is applied along and adjacent to opposite side edges of the envelope blank and then opposed portions of the side edges are folded over the portions of the blank containing the gum or adhesive so as to form the pocket of an envelope enclosure.
The gum or adhesive is applied along and adjacent to the opposite side edges of the envelope blank by rollers which are in engagement with glue transfer rollers, which in turn tangentially contact a gum roller adapted to be immersed in a container containing liquid gum or adhesive. Since the gum applying surface of the gum applying rollers are continuous and form the circumference of each of the rollers, it is difficult to accommodate successive envelope blanks in the apparatus.
If the rollers continuously supply gum or adhesive to the envelope blanks and the blanks are sequentially fed through the gumming station in spaced relation, glue will be applied to the feed belt between the envelope blanks, thereby marring the belt and rendering the apparatus inoperative as successive envelopes will adhere to the belt.
Accordingly, in the aforementioned gumming station of the envelope manufacturing apparatus disclosed, the envelope blanks are fed successively past the gum applying rollers on a conveyor belt. The belt which normally supports the envelope blank is looped beneath the gum applying rollers so that it is out of contact with the rollers at the gum applying station. At the station, the envelope blank is successively supported by the belt, an idler roller as it passes beneath and adjacent to the gum applying rollers, and back on the belt, rendering support of the blank somewhat less than adequate at the gumming station.